Red and white Chinook salmon: genetic divergence and mate choice

摘要: Chinook salmon (Oncorhynchus tshawytscha) exhibit extreme differences in coloration of skin, eggs and flesh due to genetic polymorphisms affecting carotenoid deposition, where colour can range from white bright red. A sympatric population red occurs the Quesnel River, British Columbia, frequencies each phenotype are relatively equal. In our study, we examined evolutionary mechanisms responsible for maintenance morphs, first tested whether morphs were reproductively isolated using microsatellite genotyping, second, breeding trials seminatural spawning channels, assortative mate choice could be operating maintain polymorphism nature. Next, given difference assimilation importance carotenoids immune function, selection between at genes (major histocompatibility complex genes: MHC I-A1 II-B1). individuals found interbreed, under conditions, some degree (71% matings) was observed. We significant both but no evidence II-B1-based choice. White more heterozygous II-B1 compared with individuals, showed allele frequency I-A1. Although is likely not a primary mechanism maintaining population, results suggest that differentially salmon, possibly utilization.